Angiomyolipoma arising in the colon.

1Department of Pathology, Iwate Medical University School of Medicine, Japan.

Abstract

Extrarenal angiomyolipomas are very rare. Here we report the first case of surgically resected angiomyolipoma of the descending colon that developed in a 50-yr-old man. The patient had no signs of or family history of tuberous sclerosis. He underwent a partial colectomy because the tumor obstructed the colon. Histologically, the tumor consisted of three components: mature fat cells, blood vessels, and smooth muscle cells, and was thereby diagnosed as an angiomyolipoma. Immunohistochemically, the proliferating smooth muscle cells were positive for vimentin, alpha-smooth muscle actin, and desmin. The tumor cells were negative for HMB-45, which is consistently expressed in renal angiomyolipomas.